Active and Durable PGM-Free Cathodic Electrocatalysts for Fuel … · 2020. 6. 26. · Active and Durable PGM-free Cathodic Electrocatalysts for Fuel Cell Application Pajarito Powder,

Active and Durable PGM-free

Cathodic Electrocatalysts for Fuel

Cell Application

Pajarito Powder, [email protected]

PI: Alexey Serov

This presentation does not contain any proprietary, confidential, or otherwise restricted information

Project ID # FC305

Co-PIs: Tatyana Reshetenko (HNEI) and Madeleine Odgaard (IRD Fuel Cells)

May 28, 2020

Overview

2May 28, 2020 ©2020 Pajarito Powder, LLC

• IRD Fuel Cells, Madeleine

Odgaard

• University of Hawaii, Hawaii

Natural Energy Institute (HNEI), Dr.

Tatyana Reshetenko

Partners

Barriers

• Activity of PGM-free ORR

catalysts should be increased

• Decrease a cost of PGM-free

catalysts manufacturing

• Increase the durability PGM-free

catalysts

•Project Start Date: 01/01/19

•Project End Date: 12/31/20

Timeline

•Total DOE Funds Spent to

Date: $487,983.61

•Total DOE Project Value:

$999,814.00

Budget

3

Relevance: Objectives and Targets

➢ Objectives: Development of PGM-free electrocatalysts for ORR;

the catalysts will be scaled up to 50g batches (PP); PGM-free

catalysts will be integrated into the industrial state-of-the-art MEAs

(IRD) and comprehensively evaluated by electrochemical methods

(HNEI).

➢ Relevance to DOE Mission: Inexpensive, highly active and stable

PGM-free ORR catalysts commercially manufactured by US

catalyst company will demonstrate required by DOE performance

level due to understanding the electrochemical processes relevant

to PGM-free materials in mass-produced MEAs.

➢ Targets

• Demonstrate 0.044 A/cm2 at 0.9V (iR-free, H2/O2 configuration,

1bar O2, 80ºC, 100%RH)

May 28, 2020 ©2020 Pajarito Powder, LLC

4

Approach: Catalysts and Method


Approach: VariPoreTM Method

5

Ball-Mill Pyrolysis Etching Centrifuge Filter Dry Pyrolysis

Silica Infused with precursors

Pyrolizedinfused silica

Etched pore structure

Porous non-PGM catalyst

Pore structure evolution

Pyrolized pore structure


Approach: Timeline and Milestones

6

Milestone Schedule

Milestone # Project Milestones Type

Task Completion Date (Project Quarter)

Progress Notes Original

Planned

Revised

Planned Actual

Percent

Complete

1.1 Correlation between synthesis parameters

and morphology and chemistry of catalyst Milestone 4/30/2019 4/30/2019 100%

Gen-1 is

characterized by

XRD, BET and

Raman

1.2 Deliver 10 MEAs with stock catalyst Milestone 4/30/2019 4/30/2019 100% Delivered to PP and

HNEI

1.3

Activity will be compared with

preliminary data obtained at Pajarito

Powder: 0.025 A/cm2 at 0.83V (iR-free),

with H2 /O2 at 1.0 bar O2, 100%RH, 80

°C

Milestone 4/30/2019 3/30/2019 100%

PP manufactured

MEAs which

achieved Milestone

performance.

2.1 Deliver Gen-2 catalysts Milestone 7/31/2019 7/15/2019 100%

Gen-2 synthesized by

PP. IRD made MEAs

and delivered to

HNEI and PP.

2.2

Deliver 10 MEAs with Gen-2 catalyst

Activity Targett: MEA that produces

0.025 A/cm2 at 0.85 V (iR-free), with H2

/O2 at 1.0 bar O2, 100%RH, 80 °C

Milestone 10/31/2019 8/10/2019 100% MEAs were tested.

Milestone is met.

2.3 Recommendation to improve catalyst Milestone 1/31/2020 100%

Surface area of

catalysts should be

higher than 560 m2 g-

1.

Go/No-Go #1

MEA that produces 0.025 A/cm2 at

0.90 V (iR-free), with H2 /O2 at 1.0 bar

O2, 100%RH, 80 °C

Go/No-Go 1/31/2020 100%

Post-treatment of

catalyst in ammonia

improved activity.

3.1 Deliver Gen-2a catalysts (Activity Target

in 3.3) Milestone 4/30/2020 0% Not started.

3.1 Deliver Gen-3 catalysts (Activity Target

in 3.3) Milestone 10/31/2020 0% Not started.

3.3 Deliver MEAs with Gen-3 catalyst.

Activity target: 0.044 A/cm2 at 0. 85 V Milestone 1/31/2021 0% Not started.

3.4 Estimate mass transfer losses Milestone 1/31/2021 0% Not started.

3.5

Degradation in performance BoL/EoL

MEAs to ElectroCat. Potential hold will

be done at 0.65V for 500h (with H2 /Air

at 1.0 bar Air, 100%RH, 80 °C) and

degradation rates will be reported.

Deliver 10 MEAs 50cm2 to ElectroCat

consortium partners.

Milestone 1/31/2021 0% Not started.

7

Accomplishments and Progress


• Gen-1 Catalysts Variables: N-C precursor was fixed to Pipemidic Acid, 3 types of

silica used (SA = 150, 400 and 500 m2 g-1), precursors mixtures were dried

differently (air-dried and vacuum-dried). Resulted in Fe-N-C type (SA ~500 m2 g-1)

• Gen-2 Catalysts Variables: N-C precursor was fixed to Nicarbazin, 3 types of


differently (air-dried and vacuum-dried). Heat treatment temperature was higher

compared to Gen-1. Resulted in Fe-N-C type (SA ~ 600 m2 g-1)

• Gen-2A Catalysts Variables: N-C precursor was fixed to Nicarbazin, 3 types of


differently (air-dried and vacuum-dried). Samples were ammonia treated.

• Gen-2B Catalysts Variables: N-C precursor was fixed to Nicarbazin. ZIF-8 was

used as a pore/particle former. Samples were ammonia treated.

• Gen-3.1 Catalysts Variables: Mn was added to Fe precursor. Resulted in Fe-Mn-

N-C (SA ~700 m2 g-1). Samples will be ammonia treated.

• Gen-3.2 Catalysts Variables: Addition of different amount of Urea to Fe-N-C, Fe-

Mn-N-C and other materials to increase number of Fe-Nx centers and decrease

particle size of catalysts.

8

Gen-2 (non-NH3

treated samples): high

surface area silica

resulted in formation

of several levels of

porosity.



Microscopy by Dr. David Cullen (ORNL)



Gen-2 catalysts were integrated into 25cm2 MEAs and

evaluated at HNEI (6mg/cm2 loading)

T. Reshetenko, G. Randolf, M. Odgaard, B. Zulevi, A. Serov, A. Kulikovsky

"The Effect of Proton Conductivity of Fe–N–C–Based Cathode on PEM Fuel

cell Performance" Journal of The Electrochemical Society 167 (2020) 084501



Highest performance was achieved using thinnest

membrane - 15µm (all data non-iRcorrected)

Fuel Cell Performance of Fe-N-C Gen-2 Catalysts with Different Membranes






Based on EIS modeling suggests low H+ conductivity and

ORR kinetics are limiting MEA performance

Fuel Cell EIS Modeling of Fe-N-C Gen-2 Catalysts with Different Membranes

Collaboration with Dr. Andrei Kulikovsky

15 um,

50 mA/cm2

15 um,

100 mA/cm2

25 um,

50 mA/cm2

25 um,

100 mA/cm2

Tafel slope / mV/exp 36.9 42.0 39.6 39.8

Tafel slope / mV/decade 85.0 96.7 91.2 91.7

CCL proton conductivity / mS/cm 8.83 4.94 9.12 3.96

Volumetric DL capacitance / F/cm3 14.8 19.3 10.0 22.8

CCL oxygen diffusion coeff. / 1e-4 cm2/s large large 45.2 43.9

GDL oxygen diffusion coeff. / cm2/s large large large 0.13




12

Gen-3 (NH3 treated

samples): carbon

matrix substantially

etched by NH3.

Atomically dispersed

Fe-Nx centers are

exposed.






Gen-3 catalyst (2.5 mg/cm2 loading) has much thinner

catalyst layer in 25cm2 MEA



Gen-3 catalyst shows much higher performance at both

0.9V and 0.2V (data non-iRcorrected)

Fuel Cell Performance of Fe-N-C Gen-3 Catalysts

0 200 400 600 800

0.6

0.7

0.8

0.9

1.0

0 25 50 750.7

0.8

0.9

1.0

0.0

0.2

0.4

0.6

0.8

1.0

N2PGZ-2:

no flow, warm up, 30 min

Cat. = 2.5 mg/cm2

An.= 0.2 mgPt/cm2

MEA= 23 cm2

An/Ca: H2/O

2, 500/500 ml min

-1, 100/100%RH, 150/150 kPa, 80

oC

forward, 1 IV

backward, 1 IV

HF

R [

Oh

m c

m2]

Vo

lta

ge

[V

]

Current density [mA cm-2]

Vo

lta

ge

+iR

[V

]


0 500 1000 1500 2000

0.2

0.4

0.6

0.8

1.0

0 25 50 750.7

0.8

0.9

1.0

0.0

0.2

0.4

0.6

0.8

1.0

Forward IVs

1 run IV

2 run IV

3 run IV

N2PGZ-2:

no flow, warm up, 30 min

Cat. = 2.5 mg/cm2

An.= 0.2 mgPt/cm2

MEA= 23 cm2

An/Ca: H2/O

2, 500/500 ml min

-1, 100/100%RH, 150/150 kPa, 80

oC

HF

R [

Oh

m c

m2]

Vo

ltag

e [

V]


Vo

lta

ge

+iR

[V

]


15

High throughput

optimization of NH3

treatment was done at

ANL on 50g single batch

Fe-N-C provided by PP.

More than 30 samples

were prepared and

evaluated.




High throughput ammonia treatment by Dr. Magali Ferrandon and Dr. Debbie Myers (ANL)



“Fresh” (after 2 synthetic steps of 5) has intrinsically low

activity. Substantial increase in activity after NH3 treatment

RDE Performance of Fe-N-C Gen-3.X Catalysts (ANL)

High throughput ammonia treatment, RRDE by Dr. Debbie Myers and Dr. Magali Ferrandon (ANL)

Ink recipe:

✓ 0.6 mg/cm2

✓ Catalyst: 5mg, IPA: 0.5ml, D520

Nafion: 10µl

RRDE measurement protocol:

✓ 900 RPM

✓ O2 saturated H2SO4

✓ Ag/AgCl reference electrode

calibrated vs RHE

✓ Graphite rod as a counter electrode

✓ Voltage Stair-Step:

0.95V→0.05V→0.95V, 20mV step,

10s hold



Gen 3.A catalyst reached ~1 A/cm2 at 0.6V and 2.5 A/cm2 at

0.2V

Fuel Cell Performance of Fe-N-C Gen-3.X Catalysts (ANL)

High throughput ammonia treatment, data analysis by Dr. Debbie Myers and Dr. Magali Ferrandon (ANL)

Conditions: A/C H2/O2 500/500 ml cm-2, 100% RH, 150kPabackpressure, Tcell=80C.



Team successfully met 1st Go-no-Go design point:

25 mA/cm2 at 0.9V (ElectroCat conditions)

Fuel Cell Performance and Progress Towards 1st Go-no-Go Decision

High throughput ammonia treatment, data analysis by Dr. Debbie Myers and Dr. Magali Ferrandon (ANL)

Conditions: A/C H2/O2 500/500 ml cm-2, 100% RH, 150kPabackpressure, Tcell=80C.

Catalyst Varied synthetic

parameters

Current density at

0.9V (mA/cm2)

Gen-1 Pipemedic acid as N-C

precursor

2

Gen-2 Nicarbazin as N-C precursor 9

Gen-3.A Nicarbazin as N-C precursor

with ammonia treatment

20-27

Gen-3.B Using ZIF-8 as a

particle/pore forming

25

Reviewers Comments

Comment: More planned interactions with ElectroCat could be beneficial.

Answer: Team actively collaborates with ElectroCat as well as planningto continue this collaboration (see Collaboration and Future Plans).

Comment: The approach does not include a significant effort todevelop a new catalyst.

Answer: In the 1st year Pajarito developed ~25 new catalysts among3 generations using proposed approach. The variables were: organicprecursors, types of pore formers, heat treatment and post treatmentparameters.

Comment: The team should include specific stability and durabilitytargets in addition to the performance milestones.

Answer: Team actively participates in ElectroCat workshops andonline meetings and will adopt new targets for the stability anddurability.


Collaborations

• Established materials exchanged with US manufacturers of

ionomers and membranes (Chemours, 3M and Tetramer).

• Team collaborates internationally with EU funded projects

PEGASUS and CRESCENDO as a provider of commercial Fe-

N-C catalysts and member of their Scientific Advisory Boards.

• Close collaboration with Dr. Andrei Kulikovsky on modeling of

EIS and FC data.

• Team actively collaborated with ElectroCat consortium: ANL

(high throughput synthesis of ammonia treated Fe-N-C catalysts;

characterization, Machine Learning), ORNL (microscopic study

of different generations of catalysts), LANL (evaluation of

number of active sites and TOF by probing experiments), NREL

(electrode and catalyst layer design).


Remaining Challenges and Barriers

• Increasing the number of active sites through creation of

highly defective Fe-N-C structure.

• Decreasing the particle size of primary Fe-N-C catalyst

(~600nm now). Target <300nm.

• Increasing catalyst stability and MEA durability for both

as prepared Fe-N-C and ammonia treated Fe-N-C

catalysts.

• Increasing proton conductivity in the thick catalyst layer

through the uniform three-phase interface creation.

• Compile all produced data into the database for the

usage in Machine Learning applications.


Proposed Future Work


Any proposed future work is subject to change based on funding levels

• PP: a) optimization of zinc and b) ZIF-8 synthetic parameters

(using Nicarbazin instead of phenanthroline). Initiated

• IRD: a) manufacture Gen-3.X MEAs for screening and b) optimize

ionomer/membrane for best performer of Gen-3. Done 50%

• HNEI: a) screen activity Gen-3, b) EIS study on best performer and

c) initiate a probing experiments with NO. Done 40%

• Based on the results obtained from IRD and HNEI re-formulate

catalysts morphology and surface chemistry at PP

• Team: continue collaboration with ElectroCat consortium (ANL,

ORNL, LANL and NREL)

• Apply high throughput synthesis and Machine Learning for

enhanced rational design of Fe-N-C catalysts

Technology Transfer Activities

• New generations of Fe-N-C catalysts will becommercially available after internal QC/QA.

• Pajarito jointly with General Graphene, Corp (TN,USA) applying for alternative funding in order to useFe-N-C materials in DMFC application.

• Pajarito and IRD Fuel Cells, LLC looking for enhancingjoint provisional application with novel electrodestructure (pending).

• Pajarito exploring possibilities for alternativecommercial application of Fe-N-C catalysts (2 US and2 EU companies are approached).


Any proposed future work is subject to change based on funding levels

Summary


• 25 different catalysts were synthesized on batch level of 35-50g.

• More than 275 industrial quality MEAs were manufactured by IRD on 25cm2

form-factor.

• HNEI and PP established activation protocol with minimal initial

performance degradation.

• HNEI initiated comprehensive electrochemical analysis of Gen-1, 2 and 3.X

MEAs manufactured by IRD.

• ~20 Fe-Mn-N-C, Fe-Zn-N-C and Fe-N-C (Urea) catalysts were synthesized,

integrated into CCMs and 40 MEAs delivered to Pajarito and HNEI (under)

evaluation.

• Team achieved 22-27 mA/cm2 at 0.9V (silica) and 25 mA/cm2 at 0.9V (ZIF-

8).

• 3 joint publications for 1st year, 3 oral presentations, including one invited

• Team met all Milestones and 1st Go-no-Go design point

25

Technical Back-up Slides

Technical Back-up

26

Publications and Presentations

Publications:

[1] T. Reshetenko, G. Randolf, M. Odgaard, B. Zulevi, A. Serov*, A. Kulikovsky "The Effect of Proton Conductivity of

Fe–N–C–Based Cathode on PEM Fuel cell Performance" Journal of The Electrochemical Society 167 (2020) 084501.

[2] C.L. Vecchio, A. Serov*, H. Romero, A. Lubers, B. Zulevi, A.S. Aricò, V. Baglio "Commercial platinum group metal-

free cathodic electrocatalysts for highly performed direct methanol fuel cell applications" J. of Power Sources 437

(2019) 226948.

[3] T. Reshetenko, A. Serov, A. Kulikovsky, P. Atanassov "Impedance Spectroscopy Characterization of PEM Fuel

Cells with Fe-NC-Based Cathodes" J. of The Electrochemical Society 166 (2019) F653-F660.

Presentations:

[1] A. Serov*, G. McCool, H. Romero, S. McKinney, A. Lubers, M. Odgaard, T. V. Reshetenko, B. Zulevi "PGM-Free

Oxygen Reduction Reaction Electrocatalyst: From the Design to Manufacturing", ECS Meeting 235, Dallas, TX

(2019).

[2] A. Serov*, G. McCool, H. Romero, S. McKinney, A. Lubers, M. Odgaard, T. V. Reshetenko, B. Zulevi “Are PGM-

free Fuel Cell Catalysts Ready for Prime-Time?", EFCD2019, La Grand Motte, France (2019). Invited.

[3] A. Serov*, G. McCool, H. Romero, S. McKinney, A. Lubers, M. Odgaard, T. V. Reshetenko, B. Zulevi "VariPore™:

A Powerful Manufacturing Platform for Fuel Cell and Electrolyzer Applications", ECS Meeting 236, Atlanta, GA (2019).

[4] T. Reshetenko, A. Serov, A. Kulikovsky, P. Atanassov, “Comprehensive characterization of PGM-free PEM fuel

cells using AC and DC methods”, ECS Meeting 236, Atlanta, GA (2019).


Progress: MEA Preparation

Hot pressing conditions were harmonized around 3 groups

(Pajarito, IRD Fuel Cells and HNEI):

• Press temperature of 140oC

• Press time of 4 minutes

• Press at ~2400lbs

• Cathode gasket thickness is 10mil. Anode gasket thickness

is 6mil. Compression ratio was in the range of 15-20%.

o Gaskets are supposedly rigid and non-compressible

o No variations in gasket thickness

o GDL used is Freudenberg H23C8 (220-230um thick)


Progress: Activation Protocol

Activation Protocol was harmonized at 2 groups (Pajarito

and HNEI), while IRD Fuel Cells makes additional

optimization:• MEA placed in the hardware (Fuel Cell Technology) either 25cm2

(CCMs made by IRD) or in 5cm2 (CCSs made by Pajarito)

• Cell’s temperature increased to 80ºC with no gases flowing

• When temperature stabilizes, fully humidified gases supplied to

the anode (H2 500ml cm-2) and cathode (O2 500ml cm-2)

• Backpressure adjusted to 150kPa

• After 10 minutes polarization curves recorded from OCV to 0.6V

(5 scans)

• Full polarization curves recorded from OCV to 0.2V (2 curves)

Active and Durable PGM-Free Cathodic Electrocatalysts for Fuel … · 2020. 6. 26. · Active and Durable PGM-free Cathodic Electrocatalysts for Fuel Cell Application Pajarito Powder,

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